This invention relates generally to travel route planning; and specifically to hazard avoidance.
Travel route planning is critically important to maintaining safe passage in a non-constrained mode of travel. Non-constrained travel modes typically comprise any mode of travel that is not confined to a specific route, i.e. a road. Hence, air travel, marine navigation and even space travel comprise some example modes of non-constrained travel. Aquatic submarines are also non-constrained vehicles. In aircraft travel, flighty safety hinges on proper flight planning. Flight plans are a required part of flight procedures as mandated by government agencies. In addition, flight planning is an ongoing activity during most flights due to changing weather conditions. This is true for marine navigation as well. In space, flight planning defines each leg of a flight from lift-off to orbit to re-entry and to landing.
The travel route planning practice has evolved over time. This evolution has fundamentally been driven by a simple goal: arriving safely at an intended destination. One aspect of travel route planning, which is especially true in non-constrained modes of travel, is that of determining the location of hazardous objects and avoiding them along the way to the final destination. Determining where hazardous objects are in time to avoid them has always been a central challenge of travel route planning. Initially, this was accomplished visually; pilots or mariners would travel along their intended route and avoid an obstacle or other hazard in due course.
These visual methods were normally compromised by poor visibility and the general inability to determine if an object was hazardous at a distance. Travelers would often find themselves in a hazardous storm before they realized its dangerous nature. As technology became more enhanced, methods such as radio reports, radar detection, and satellite systems have become extended sensors that can be used to warn pilots or mariners of hazardous objects along their intended travel route. With this type of technology, travel route planning evolved to a new level of proficiency. Flight plans and other intended travel routes could now be based on knowledge of obstacles hundreds of miles ahead of the craft.
Although the enhancements of modern technology greatly improved travel route planning and the ability to identify hazardous targets at great distances, the general operational schema of exploiting this information has remained difficult and tedious. Some of the remaining challenges to travel route planning include, but are not necessarily limited to estimating the impact of moving hazardous objects, simplifying travel route definition so as to simplify the route planning process, and optimizing travel route plans to decrease travel time and/or conserve fuel.
Now that sensor and communication technology has brought together the necessary information to construct a static travel route plan over great distances, what is needed is a way to quickly derive the best travel route plan and rapidly update it as conditions change.
The present invention comprises a method and an apparatus for identifying hazards along a travel route plan and then providing the results of the assessment to an output port. In some cases, the output port may be coupled to a display adapter for presenting the hazard assessment to a human user. The human user may be a pilot, another member of the flight crew or any other user who may have a need for an assessment of hazardous conditions along a travel route plan. Relying on a wide variety of sensory inputs, the method of the present invention comprises a first step of receiving a target message that defines the position of a target. In some embodiments, the method provides for a first filtering step that identifies targets that may lie along the travel route plan within a predefined buffer zone. Once a target has been identified as being within this buffer zone, it is evaluated to determine if the target may be hazardous to the safety of a vehicle. The buffer zone may be received either from a human user or from a predefined zone stored in some computer readable media.
According to one illustrative method of the present invention, determining the hazardousness of a target may comprise a simple step of comparing the target to predefined hazardous condition criteria. In one example, a target may be identified as being hazardous if it meets the criteria of being a thunderstorm. This, though, is just one example of possible hazard criteria that may be applicable to the method of the present invention and should not constrain the scope of the invention. Other illustrative hazard comparisons may comprise other hazardous weather, terrestrial fixtures and high-elevation terrain. According to one illustrative method of the present invention, targets are tracked using target descriptors. Hence, target attribute data may be retrieved from a target descriptor and used as the basis for the hazard evaluation.
Once a target has been identified as being hazardous, it is marked as such. For a target that has been marked as hazardous, the method of the present invention suggests the creation of a geometric representation of the hazardous target. On a periodic basis, the method of the present invention requires an assessment of the intrusiveness of the geometric representation of the hazardous target into a geometric representation of the vehicle projected along the travel route plan of the vehicle in time or distance. According to this illustrative method, the assessment of intrusiveness may then be presented. This presentation may be made to an output port or presented to a human user. It should be noted that the geometric representation of either the vehicle or a target may either be generated locally onboard the vehicle or received from off-vehicle sources.
According to one illustrative embodiment of a method according to the teachings of the present invention, assessing the intrusiveness of the geometric representation of a hazardous target into the geometric representation of the vehicle may require partitioning the required projection into a finite number of increments. Typically, the amount of projection required is expressed in either time or distance of travel. For each successive increment, the geometric representation of the vehicle is projected to the end of the increment. If this projected geometric representation of the vehicle is found to be coincident with the geometric representation of a hazardous target, the method of the present invention provides for setting a hazard-warning-flag for that particular segment of the travel route plan corresponding to the increment.
Presentation of the assessment of intrusiveness may be accomplished in a similar manner. According to this illustrative method, the travel route plan of a vehicle may be partitioned into a plurality of segments. Each of the segments may then be displayed to a user. For each segment that has a corresponding hazard-warning-flag set active, the segment displayed may be highlighted to indicate that that segment of the travel route plan may be associated with a hazardous target. The method of assessing intrusiveness where only the vehicle is projected is typically referred to as a static target method.
Highlighting the particular segment comprises one aspect of the illustrative method taught here. Such highlighting may be accomplished by painting a line parallel to and offset from the segment that needs to be highlighted. Drawing two parallel lines that straddle the segment to be highlighted might also accomplish highlighting. In yet another alternative highlighting method taught by the present invention, displayed segments may be flashed or drawn in an alternative color to ensure that a user notices the hazardous nature of a particular segment of the flight plan.
According to an alternative illustration of the method of the present invention, a target message that is received from various sensory devices may comprise a motion vector for a particular target. This motion vector may be extracted from the target message and used to project the geometric representation of a hazardous target in time or distance. According to the teachings of the method of the present invention, this projected geometric representation of a hazardous target may be used in conjunction with the projected geometric representation of the vehicle to determine intrusiveness. This method is typically referred to as dynamic intrusiveness assessment. Once the dynamic intrusiveness has been assessed, it may then be presented to an output port or to a human user in a manner akin to that already described for a static target intrusiveness assessment.
Dynamic intrusiveness may be assessed by first partitioning the required time or distance of projection into a finite number of increments. For each increment, the geometric representation of the vehicle may be projected along its travel route plan and the geometric representation of the hazardous target may be projected along its motion vector. For every segment, a hazard-warning-flag may be set to indicate coincidence of these two projected geometric representations.
The method of the present invention may receive target messages from a wide variety of sources. One such source may be an onboard radar system. According to this illustrative method, a radar image may be received from such an onboard radar system and used to identify targets. Each of these targets may result in the creation of a target descriptor. According to this illustrative embodiment, target descriptors may define the position of a target either relative to the vehicle or relative to a global coordinate system.
In one alternative embodiment of a method according to the present invention, target attributes may be either created or received and then stored in a target descriptor. Such attributes may include, but are not necessarily limited to speed and direction of travel (i.e. motion vector) and size of the object. For the case where a target descriptor is created in response to a target identified by onboard sensors, additional processing onboard the vehicle may generate such attributes data. In the case were a target descriptor is created in response to a target message received from an off-vehicle target tracking system, such attribute data may comprise the target message and is typically extracted from the message and then stored in the target descriptor.
The method of the present invention also allows for the reception of target messages from off-vehicle tracking systems. Such messages may also comprise position information that may define the position of a target either relative to the vehicle or relative to a global coordinate system.
In a general illustrative embodiment of a method according to the present invention, a first target message may result in a target descriptor. Other target descriptors may be generated in response to other target messages received from other sensory devices, either onboard or off-vehicle sourced. The first target descriptor may then be correlated with other target descriptors in order to identify which target descriptors may represent the same target. When these are identified, all attribute data may be combined to form a union of all attribute data pertinent to a particular target and stored in one target descriptor comprising a fusion of all of the attribute data.
In some embodiments of the present method, the geometric representations of targets or a vehicle may either be generated locally onboard the vehicle or they may be received from external sources. The geometric representation, according to one illustrative method of the present invention, may comprise a point in two or three-dimensional space. The geometric representation may alternately comprise a line defined by two end points. The geometric representation may also be defined by three or more points that collectively define the perimeter of a portion of a plane. Targets or a vehicle may likewise be represented by geometry comprising an ellipse. In this case, an ellipse may be specified according to two focal points with at least one point that controls the focal length of one or both focal points. An ellipse of this type may be used to define a portion of a plane lying within its perimeter in either two or three-dimensional space.
According to some illustrative methods of the present invention, the geometric representation of a target or a vehicle may comprise a three-dimensional volume. According to one example, a three-dimensional volume may be defined by specifying four or more points to defined a three-dimensional volume having linear boundaries. Abstract shapes may be represented by defining two or more points coincidence with the ends of a Bxc3xa9zier curve. Additional points may be used to defined curvature of the Bxc3xa9zier curve as it approaches one of its end points. The Bxc3xa9zier curve may also be revolved around a straight axis defined by its two end points through a specified sweep angle in order to define an abstractly shaped three-dimensional volume.
The present invention also comprises an apparatus that embodies the method of the present invention. According to one such illustrative embodiment, a travel hazard assessment device may comprise an input port for receiving target messages and flight plans. A buffer zone manager, that also comprises the travel hazard assessment device, may determine if target messages correspond to targets that lie within a predefined buffer zone along a travel route plan. According to this example of embodiment of the present invention, a travel hazard assessment device may also comprise a criticality manager that determines which targets within the buffer zone constitute hazards.
According to this one example embodiment of a travel hazard assessment device, the target shape manager comprising an apparatus that creates or receives geometric representations for a target once that target is marked as hazardous. The invention may further comprise an intrusion detector that periodically determines if the geometric representation of the hazardous target intrudes upon the travel route plan received by means of the input port. A display unit also comprises the invention and is used to display segments of a travel route plan to a human user. Particular segments along the travel route plan may be highlighted as an indication that hazardous targets may be proximate to the planned route of the vehicle.
In one alternative embodiment of a travel route hazard assessment device, the invention may comprise a processor coupled to working and program memory that also comprise the invention. The travel route hazard assessment device may also comprise a display adapter coupled to the processor. The display adapters typically capable of driving a display device and is ordinarily controlled by directives generated by the processor under program control.
In this alternative embodiment of a travel route hazard assessment device, a travel route hazard assessment instruction sequence is stored in program memory. The travel route hazard assessment instruction sequence minimally may cause the processor to receive a target message that minimally defines the position of a target. In this example of embodiment, the processor will typically receive the target message from an input port that also comprises the invention.
According to this example of embodiment, the travel route hazard assessment instruction sequence will cause the processor to store the travel route plan in working memory. The processor typically generates a geometric representation of the vehicle and stores this in the working memory. For targets that are hazardous and that lie within the buffer zone along a travel route plan stored in the working memory, the processor will create or receive a geometric representation of the target. The processor may also periodically assess if the geometric representation of the vehicle intrudes upon by the geometric representation of a hazardous target. The travel route hazard assessment instruction sequence typically causes the processor to present the results of this assessment.
In order to accomplish intrusion assessment, the travel route hazard assessment device of the present invention may further comprise an intrusion assessment instruction sequence stored in the program memory. The processor may execute this instruction sequence that will minimally cause the processor to retrieve from the working memory the minimum amount of projection in time or distance that must be performed in the assessment. This time or distance may then be partitioned into a finite number of increments. For each increment, the processor may project the geometric representation of the vehicle along the travel route plan stored in working memory. The processor will also set a flag in working memory for the segment of the travel route plan corresponding to the increment if the projected representation of the vehicle is at all coincidence with the geometric representation of a hazardous target.
In one illustrative embodiment of the travel route hazard assessment device, the invention comprises a presentation instruction sequence also stored in program memory. The processor may call the presentation instruction sequence to display the results of the intrusion assessment created by the intrusion assessment instruction sequence. The presentation instruction sequence may minimally cause the processor to partition the travel route plan stored in working memory into a plurality of segments. In each segment of the flight plan, the processor will typically send paint commands to the display adapter. The processor will also typically retrieve a hazard-warning-flag from the working memory that corresponds to a particular segment. If that flag is active, the processor will send a highlighting command to the display adapter for that ,particular segment.
The presentation instruction sequence may dispatch various highlighting commands to the display adapter. According to one example embodiment, the processor may send a parallel line command to cause the display adapter to paint a line parallel to and offset from the segment to be highlighted. In yet another example embodiment, the processor may dispatch two parallel line commands causing the display adapter to paint two parallel lines that straddle the segment to be highlighted. In yet another illustrative embodiment of the present invention, the highlighting command may comprise a flash command that causes the display adapter to flash the segment to be highlighted. The present invention may also comprise the use color change command for highlighting a particular segment of a flight plan.
In one example embodiment of the present invention, as already introduced supra, the processor may only conduct a static target evaluation. The travel route hazard assessment instruction sequence may further cause the processor to determine a motion vector for a target marked as hazardous. In this case the travel route hazard assessment instruction sequence may also cause the processor to periodically determine the intrusiveness of a hazardous target by projecting the geometric representation of the target stored in working memory along a motion vector and by projecting the geometric representation of the vehicle stored in working memory along the travel route plan is also stored in working memory. These projections may be accomplished according either to time or distance.
In this illustrative embodiment of the present invention, the processor may execute a dynamic intrusion instruction sequence stored in program memory and further comprising the invention. Accordingly, the dynamic intrusion instruction sequence may retrieve a minimum projection time or distance from the working memory. This time or distance may be partitioned into a finite number of increments. According to this illustrative embodiment, the processor may project the geometric representation of a target along the target""s motion vector to the end of an increment. This may be compared to the projection of the geometric representation of a vehicle along the travel route plan stored in working memory. In the event that the two geometric representations overlap, a flag may be set in working memory for the segment of the travel route plan corresponding to the increment where the overlap occurs. A dynamic intrusion presentation instruction sequence may also comprise the invention and is typically stored in the program memory. This presentation instruction sequence is analogous to its static counterpart. This presentation instruction sequence may be used to present the results of such a dynamic intrusiveness assessment in some embodiments of the present invention.
In one typical embodiment of the present invention, the travel route hazard assessment device may receive target data from a wide variety of sensors. Target data from both onboard and off-vehicle sensors may be received. In one embodiment, the travel route hazard assessment device may further comprise a, radar target extraction instruction sequence that is stored in program memory. This instruction sequence may cause the processor to perceive an image from an onboard radar system and to identify targets comprising the image. For each target identified, the processor may typically create an onboard-sourced target descriptor that minimally defines the position of a target either relative to the vehicle or relative to a global coordinate system. The processor typically stores this descriptor in working memory
In those embodiments that comprise a radar target extraction instruction sequence, this instruction sequence ray further cause the processor to create target attributes for each identify target. These target attributes may then be stored in the working memory. Typically, the target descriptor is retrieved from working memory and augmented with the attributes. The augmented descriptor may then be stored in working memory.
According to one embodiment of the present invention, the travel route hazard assessment instruction sequence may further cause the processor to execute general target processing instruction sequence that further comprises the invention and is stored in program memory. This instruction sequence may cause the processor to receive a target message from a target tracking system. This target message minimally defines the position of a target that the processor uses to create a target descriptor that defines the position of the target relative to the vehicle or relative to a global coordinate system. The general target processing instruction sequence may also cause the processor to extract target attribute data from the target message and to store this in the target descriptor. In some embodiments, the general target processing instruction sequence also causes the processor to extract a motion vector form the target message and to store this in the target descriptor.
In yet another alternative embodiment of the present invention, the travel route hazard assessment device may further comprises a weather target receiver instruction sequence stored in program memory. This weather target receiver instruction sequence typically causes the processor to receive a weather cell report and to create a target descriptor from the report that defines the position of the target either relative to the vehicle or relative to a global coordinate system. This weather-sourced target descriptor may then be stored in working memory. This same instruction sequence may also extract-weather cell attributes from the weather cell report and store these in the target descriptor.
According to one example embodiment of a travel route hazard assessment device, a buffer zone scan instruction sequence further comprises the device stored in program memory. The buffer zone scan instruction sequence causes the processor to accept a buffer zone definition from a user or to retrieve a buffer zone definition from working memory or other computer readable media. This buffer zone definition may be used to determine the extent of a buffer zone along the travel route plan stored in memory. Target descriptors lying outside of the buffer zone may be marked as xe2x80x9cno-processxe2x80x9d. This precludes the processor from performing an assessment of intrusiveness for those targets.
The travel route hazard assessment device of the present invention may further comprise a hazard identification instruction sequence stored in the program memory. This instruction sequence typically causes the processor to retrieve a target descriptor from working memory and extract from the target descriptor a first attribute. This first attribute may then be compared against a list of a hazard types. If the first attribute matches an entry in the list and hazard types, the hazard identification instruction sequence typically causes the processor to set to a hazard by comprising the corresponding target descriptor stored in the working memory. According to one embodiment of the present invention, the hazard flag may be sent by the processor if the first attribute indicates that the target is hazardous weather. In yet another illustrative embodiment, the hazard flag may be sent by the processor if the first attribute matches a hazardous terrestrial fixture category. Alternately, the hazard flag may be set active in the first attribute indicates that the target corresponds to high altitude terrain. These example hazard comparisons are not intended to limit the scope of the present invention.
The travel route hazard assessment device of the present invention may further comprise a geometric representation instruction sequence that is stored in program memory and causes the processor to represent a target as a point in three-dimensional space. This is typically carried by the target descriptor stored in working memory. In yet another alternative example embodiment, the processor may represent a target as a lying comprising to endpoints. These, too, are stored in working memory. The geometric representation instruction sequence they also cause the processor to store three points representative of a portion of a plane. These points are also stored in the target descriptor corresponding to the target and stored in working memory. A target may also be represented geometrically by an ellipse. In this case, the processor is causes to store in the target descriptor corresponding to the target to points to define the focal points of an ellipse and at least one control point that controls the focal length of either one or both of the focal points.
The geometric representation instruction sequence may also cause the processor to define a target in terms of a three-dimensional volume. In one alternative embodiment of the present invention, the processor may store for points representative three-dimensional volume having linear boundaries in a target descriptor corresponding to the target and stored in working memory. In yet another alternative embodiment of this invention, the geometric representation instruction sequence may cause the processor to define the extents of a target using a Bxc3xa9zier curve defined by two and points and at least one points to control the curvature of the, Bxc3xa9zier curve present approaches one of the endpoints. An irregularly shaped volume may be defined by causing the Bxc3xa9zier curve to sweep around a straight access defined by its two and points.
The present invention further comprises a method for aggregating target messages. According to this method, target messages may be received from various sources either on or off the vehicle. The messages are first received and target descriptors corresponding to each message comprising position and attribute data carried by the target messages are created. The plurality of target descriptors may then be correlated in order to identify a set of target descriptors that represent the same target. The attribute data from each target descriptor in the identified set may then be aggregated into a single target descriptor.
This method is also embodied in a target aggregator that also comprises the present invention. A target aggregator according to the teachings of the present invention comprises an input port that receives target messages. The target aggregator may also comprise an output port for transmitting fused target descriptors. The processor, program memory and working memory also comprise the target aggregator. The target aggregator may comprise an aggregator instruction sequence stored in the program memory and when executed by the processor causes the processor to receive a plurality of target messages from the input port. The processor may then extract position and attribute data from the plurality of target messages and may create a plurality of target descriptors in working memory comprising this data. Accordingly, the processor may correlate the plurality of target descriptors in order to identify a set of target descriptors that represent the same target. From this set, the processor will collect attribute data in order to create and aggregated target descriptor that comprises a union of all attribute data comprising the target descriptors in the identified set. The aggregated target descriptor may then be conveyed to the output port by the processor.